The inventor has proposed in the earlier Chinese patent application No. CN 201310467918.2 a power system of a tandem-type hybrid vehicle, the power system of a tandem-type hybrid vehicle using two or more independently controllable auxiliary power units, wherein each of the auxiliary power units comprises an engine, and the tandem-type hybrid vehicle can be provided with an appropriate number of engines used in combination as needed, which simply and reliably solve the problem that the power and torque of a previous single engine are limited and cannot meet the high power and torque requirements of vehicles. The inventor found in the test on the tandem-type hybrid vehicle that a large number of engines will result in a reduction in the available space in the tandem-type hybrid vehicle, affecting the experience of passengers in the vehicle.